The Class 10000 ISO7 (“I-S-O-seven”) standard for these facilities (10[1])requires an ACH (“A-C-H”) of an inverse minute. While at Sandia National Lab, Willis Whitfield pioneered usage of laminar flow in these facilities. (10[1]-5[1])Clair Cameron Patterson (10[1])effectively turned his lab (10[1])into one of these (10[1])facilities (10[1])while (10[1])trying to date (10[1])the Earth. (10[4]-5[1])In the (10[1])“recirculating” (-5[1])class of these facilities, (10[1])flow (10[1])is drawn (10[2])into the ceiling plenum (10[2])before being (-5[1])passed (10[1])through a HEPA (“HEP-uh”) system. (10[2]-5[3])NASA’s (10[2]-5[1])Goddard Spaceflight (10[1]-5[1])Center has the world’s (10[1])largest (10[1])one (10[1]-5[2])of these (10[1]-5[1])facilities (-5[4])where assembly (10[2])of (-5[1])sensitive (-5[1])equipment (10[2])occurs. (10[2]-5[3])Semiconductor (10[3])fabs contain (10[1])these (10[1])tightly controlled facilities (10[1])where integrated circuit manufacture (10[1])occurs. (10[1])For 10 points, people must take an “air shower” (10[1])before (-5[1])entering (10[1])what (10[1])spaces (10[1])with very low airborne particulate (10[1]-5[2])concentrations? (10[2]-5[1])■END■ (10[11]0[10])